## Tuesday, January 20, 2015

### Adjustment for Multiple Comparison Tests with R: Resources on the web

1. Bonferroni correction

2. Sidak (Dunn-Sidak) correction

3. Holm-Bonferroni correction

4. Hochberg correction

5. Hommel correction

6. Benjamini-Hochberg correction

or equivalently

7. Benjamini–Yekutieli (Benjamini–Hochberg–Yekutieli) correction

## Wednesday, February 5, 2014

### ggPlot2: Histogram with jittered stripchart

Here is an example of a Histogram plot, with a stripchart (vertically jittered) along the x side of the plot.

Alternatively, using the geom_rug function:

Of course this simplicistic method need to be adjusted in vertical position of the stripchart or rugchart (y=-2, here), and the relative proportion of points jittering.

## Sunday, February 2, 2014

### Boxplot with mean and standard deviation in ggPlot2 (plus Jitter)

When you create a boxplot in R, it automatically computes median, first and third quartile ("hinges") and 95% confidence interval of median ("notches").

But we would like to change the default values of boxplot graphics with the mean, the mean + standard deviation, the mean - S.D., the min and the max values.
Here is an example solved using ggplot2 package. Plus here are represented points (the single values) jittered horizontally.

## Saturday, September 17, 2011

### Implementation of the CDC Growth Charts in R

I implemented in R a function to re-create the CDC Growth Chart, according to the data provided by the CDC.

Then unrar the file, and put the Growth folder in your main directory, as selected in R. You are now able to use the two functions i'm going to illustrate.

growthFun.R

The function growthFun allows you to draw 8 different growth chart, which are different for Male and Female (sixteen in total).
The only parameters you need to input are:
sex = c("m", "f")
type = c("wac36", "lac36", "wlc", "hac", "wsc", "wac20", "lac20", "bac")
The explanation for the type's parameters code are in the first part of the function code.
Eventually you can modify the pat variable, if you want to put the Growth folder in another place (not in the main directory of R).

I reccomend to use the pdf() graphic device for best resolution.

Hese is an example of the output you can obtain, with the following code:

pdf("hac_example.pdf", paper="a4", width=0, height=0)
growthFun("m", "hac")
dev.off()

MygrowthFun.R

The function MygrowthFun allows you to personalize the output of the previous function, with specific patient's data.
The parameters you can modify are:
sex=c("m", "f")
type=c("wac36", "lac36", "wlc", "hac", "wsc", "wac20", "lac20", "bac", "bmi.adv")
path="./Growth/"
name = NULL
surname = NULL
birth_date = NULL
mydataAA = NULL

The three parameter sex, type and path are the same of the growthFun function. The three parameters name, surname and birth_date refer to the patient's data; you can add this data in form of character().
mydataAA is an optional parameters with the values measured on your patients during the time you follow up him. Generally you need to input this data in form of a data.frame().
In the type parameter there is an additional choice: bmi.adv allows you to obtain three chart (wac20, lac20, bac - see the explanation codes), if your mydataAA dataframe contains data about Stature and Weight during the time of follow up.

Details.
Let's see the format of mydataAA, according to the type of chart you want to graph.

type = wac36
mydataAA:
first column = months of measurement, from 0 to 36
second column = weight (in kg)

type = lac36
mydataAA:
first column = months of measurement, from 0 to 36
second column = length (in cm)

type = hac
mydataAA:
first column = months of measurement, from 0 to 36
second column = head circumference (in cm)

type = wac20
mydataAA:
first column = months of measurement, from 24 to 240 (from 2 to 20 years)
second column = weight (in kg)

type = lac20
mydataAA:
first column = months of measurement, from 24 to 240 (from 2 to 20 years)
second column = stature (in cm)

mydataAA:
first column (months) = months of measurement, from 24 to 240 (from 2 to 20 years)
second column (stature) = stature (in cm)
third column (weight)= weight (in kg)

In the last type it's not importat the order of the columns, but here are important their names.

Examples.
Let's see some example. Suppose that you are following the growth of a new born (her name is Alyssa Gigave, born on 07/08/2009), and you collect the following data:

Months  Length
0 50
2 55
3 56
5 61
8 71
9 72
12 75
15 75
18 81
21 89
26 91
27 94
30 95
35 98

So you can create your personalized graph in this way:

alyssa_data <- data.frame(   months=c(0, 2, 3, 5, 8, 9, 12, 15, 18, 21, 26, 27, 30, 35),   length=c(50, 55, 56, 61, 71, 72, 75, 75, 81, 89, 91, 94, 95, 98))  pdf("alyssa_growth_chart.pdf", paper="a4", width=0, height=0)  MygrowthFun(sex="f", type="lac36", name="Alyssa", surname="Gigave", birth_date="july 08, 2009", mydataAA=alyssa_data)  dev.off()

The output is the following pdf file:

Now suppose that you're a pediatric doctor, and that you follow a boy (Tommy Cigalino, born on 07/08/1980). Whenever he has come to you, you collect his weight and stature, and the months from his birth he was. So you have the following data:

months stature weight
25 98 17
31 100 21
34 102 27
35 104 29
58 106 30
60 109 32
70 111 33
85 118 34
88 119 36
89 120 39
91 121 42
102 126 45
107 128 47
108 135 49
120 144 51
134 145 52
154 148 54
166 152 55
169 157 62
170 158 63
178 163 64
179 167 68
181 168 71
219 169 74
234 176 76

So you can create three graphs (wac20, lac20, bac), using the bmi.adv type:

tommy_data <- data.frame(  months = c( 25, 31, 34, 35, 58, 60,               70, 85, 88, 89, 91, 102,               107, 108, 120, 134, 154,               166, 169, 170, 178, 179,               181, 219, 234),   stature = c( 98, 100, 102, 104, 106,               109, 111, 118, 119, 120,               121, 126, 128, 135, 144,               145, 148, 152, 157, 158,               163, 167, 168, 169, 176),   weight = c( 17, 21, 27, 29, 30, 32,               33, 34, 36, 39, 42, 45,               47, 49, 51, 52, 54, 55,               62, 63, 64, 68, 71, 74,               76))  pdf("tommy_growth_chart.pdf", paper="a4", width=0, height=0)  MygrowthFun(sex="m", type="bmi.adv", name="Tommy", surname="Cigalino", birth_date="july 08, 1980", mydataAA=tommy_data)  dev.off()

Tommaso MARTINO, 17/09/2011

REFERENCES

• http://www.cdc.gov/growthcharts/cdc_charts.htm

• http://www.cdc.gov/growthcharts/clinical_charts.htm

• http://www.cdc.gov/growthcharts/percentile_data_files.htm

• Kuczmarski RJ, Ogden CL, Guo, SS, et al. CDC growth charts for the United States: Methods and Development. Vital Health Stat; 11 (246) National Center for Health Statistics. 2002.

## Wednesday, September 7, 2011

### R is a cool sound editor!

Capabilities of R are definitely unless! After my previous posts about some easy image editing in R (they are here, and here), now is the time to explore if R is capable of sound editing!

Just for fun, here I created a function that receives a phone number (or another sequence of numbers), and returns the equivalent melody you can listen if you press that sequence on your house' phone... =D

It requires the sound library, and here's the code.

Now you can simply create your phone melody =)

s2 <- PlayTel("556c885a4623#")

You can listen to it with the command:

play(s2)

(NOTE: in Windows 7 I was unable to find a wave player that works on batch mode - i.e. mplay32.exe. So this command doesn't work on Windows 7. It works on Windows XP)

You can save the output using the command:

saveSample(s2, "tel.wav")

(This command works on Windows 7)

Here is an example of the output:

Have fun!! =)